1. Field of the Invention
This invention relates to a method of taping a harness comprising a bundle of cables, and a machine therefor.
2. Summary of the Prior Art
In French patent application FR 2 707 828, a method and apparatus for making a harness comprising electrical wires or other types of wires is described. The method described in the latter patent is particularly adapted for linear harness making machines comprising conveyor systems arranged in a straight line, that transport the harness therealong for processing. In the latter patent, the method is particularly concerned with manufacturing of a complex harness with a number of branches leading to various connection ends, where branches are held together at their joining points or nodes. In order to neatly branch off wires at a node, the harness is taped or tied at the nodes. Long sections of wires between nodes are however not held together, although the harness could be taped at intermediate positions between the nodes. It is however desirable in certain applications to keep the wires bundled together along the whole length between nodes, as exposed individual wires can get: caught on external objects. It may also be desirable to tape the whole harness with a protective layer to prevent damage to individual wires.
In the event that taping of the whole harness is desired, it is typical to take a harness, for example which is prepared by the method in the above mentioned patent, or which is manufactured manually on a wiring board, and transport the harness to a taping machine. A known taping device 10 is shown in FIGS. 1a and 1b. The device comprises a static support 1 with a bearing 6, within which a large wheel 2 is rotatably mounted, further comprising a tape roll 3 mounted on an axis 7 pivotally to the wheel 2 and comprising a tape 5. The tape is spiralled around a section 4 of harness comprising a plurality of wires (not shown). The wheel 2 and support 1 have a U-shaped slot 8 to enable the harness section 4 to be positioned in alignment with the axis of the wheel. The wheel can then be rotated in the rotation direction R whilst the harness is fed in the axial direction such that the tape unrolls from the roll 3 and winds in a spiral around the harness.
The section of harness to be taped, is supported typically by two grippers at either end, for example, positioned proximate nodes of the harness, the grippers being pulled apart to straighten the cable. The harness is manually fitted to the grippers, but the axial feeding and rotation of the wheel may be motor driven. The above method only enables a single section of harness between nodes to be taped, without intervention of an operator. An operator has to remove and reset the tape in the grippers when another section of the cable between different nodes, must be taped. This is a labour intensive and therefore costly procedure.
Due to the complexity of certain harnesses with different numbers of nodes and branches and lengths of harness between the nodes, a solution for automating the taping procedure in a sufficiently simple and viable manner has not been found. Intervention of an operator to reposition the harness on the guides for each section of harness between nodes has the advantage of at least being a simple procedure with great flexibility (i.e. different cables can be easily treated in small production runs). A further problem of the prior method, is also the possibility of inconsistent quality and therefore in certain cases defects in the harness.
It would however be desirable to render the harness making procedure less labour intensive, in a cost effective manner, whilst ensuring flexibility, simplicity and reliability of the harness making procedure.